Neplanocin A, which is isolated from Aspergillus niger, is the carbocyclic nucleoside which inhibits S-adenosylhomocystein hydrolase (SAH). SAH hydrolase is an enzyme that catalyzes the hydrolysis of S-adenosylhomocystein into adenosine and L-homocystein, and it has been reported that S-adenosylhomocystein is accumulated in the cell and exhibits antiviral activity by inhibiting S-adenosyl-L-methionine (SAM) dependent methyltransferase which is crucial for methylation in the cell as a feedback when SHA hydrolase is inhibited. (Turner et al., Cell Biochemistry and Biophysics 2000, 33, 101-125. Cantoni, G. L., In Biological Methylation and Drug Design., Borchardt, R. T., Creveling, C. R., Ueland, P. M., Eds. Humana Press: Clifton, N.J., 1986; pp 227-238; and Wolfe, M. S and Borchardt, R. T. J. Med. Chem. 1991, 34, 1521-1530 and the proofs cited in the above references).
Therefore, many compounds for inhibiting SAH hydrolase have been synthesized and neplanocin A, among them, has been reported to exhibit the potent anticancer and antiviral activity. Fluoro-neplanocin A has been synthesized based on the structure of neplanocin A and reported to exhibit the potent antivirus activity (Keller et al. In Biological Methylation and Drug Design., Borchardt, R. T., Creveling, C. R., Ueland, P. M., Eds. Humana Press: Clifton, N.J., 1986; pp 385-396).

Meanwhile, homoneplanocin A, derived from neplanocin A by adding one carbon, has also been reported to exhibit the potent inhibitive activity against SAH hydrolase (Shuto et al. Med. Chem. 1996, 39, 2392-2399)and the potent activity against hepatitis B virus. (Yang, M.; Schneller, S. W.; Korba, B. J. Med. Chem. 2005, 48, 5043-5046). Researchers have tried to synthesize fluoro-homoneplanocin A by combining fluoro-neplanocin A with homo-neplanocin A, using a conventional method. However, since it was difficult to prepare a derivate with one additional carbon using the conventional methods, fluoro-homoneplanocin A could not be prepared.
Accordingly, the present inventors have identified that the fluoro-homoneplanocin A can be synthesized by using (1S,4R,5S)-3-Ethenyl-4,5-(O-isopropylidenedioxy)-4-cyclopent-2(3)-en-1-ol as a starting substance, which can be synthesized by using D-ribose, also as a starting substance, through enynering-closing metathesis. (Jeong et al., Med. Chem. 2003, 46, 201-203. Lee et al., Med. Chem. 2011, 54, 930-938). Also they identified that the uracil- or cytosine-substituted nucleoside derivative can be synthesized using the above compounds as starting substances. The present inventors completed the present invention by identifying that the fluoro-homoneplanocin. A with the novel structure obtained by the above synthesis has an inhibitory effect against cancer cells as an anticancer drug.